1. Field of the Invention
This invention relates generally to a lumbar support, and more particularly to an adjustable lumbar support installed in a seatback of a vehicle seat.
2. Description of the Prior Art
A lumbar support installed in a vehicle seatback is used for changing or adjusting the firmness of seat spring in the seatback in order to reduce the back fatigue of an occupant who sits on the seat of a vehicle for a long time without standing or moving therefrom. The adjustment of the lumbar support usually is carried out by turning a lever or a knob provided at a side portion of a seat (such as a lever 14 or 16 shown in FIG. 1). When the lever is rotated, a cam member, provided within the seatback and operatively connected to the lever, is rotated to move a support plate in a horizontal direction (usually in a vehicle longitudinal direction). This movement of the support plate permits regulation of the degree of pressure or the hardness of the cushion of the seatback designed to be aligned with the lumbar region of the occupant of the seat.
Such conventional lumbar support, however, has ignored the hight differences in the lumbar position of users of such seatback. Without the capacity of adjusting the height of a lumbar support for a seatback, the most appropriate and comfortable lumbar support for each individual cannot be obtained.